OBJECTIVETo compare biological characteristics between nucleus pulposus and annulus fibrosus cells in vitro model.

METHODSFive New Zealand white rabbits (2 to 3 kg, either gender) were isolated nucleus pulposus and annulus fibrosus under sterilized condition, then cultured in nutrient solution with 15% FBS and DMEM/F12 (1:1) by enzyme digestion combined with tissue block method. When 90% cells fused, subcultring were performed. Cell morphology were observed by inverted phase contrast microscope, cell viability were detected by trypan blue staining, histological were observed by a toluidine blue and HE staining, cell proliferation were tested by MTT method, then the cell morphology, viability, proliferation between nucleus pulposus and annulus fibrosus were compared.

RESULTSThere were no obviously differences between nucleus pulposus and annulus fibrosus in original and the first strain. Physalides were appeared in annulus fibrosus on the second generation. The strapping time was later, and activity was lower in nucleus pulposus than annulus fibrosus. The growth of cell proliferation in nucleus pulposus was lower than annulus fibrosus from the ninth day.

CONCLUSIONThe cell activity in annulus fibrosus is higher than nucleus pulposus. Digenerative disc disease may caused by recession of nucleus pulposus,local biomechnical changes, furether caused structure change and function loss of annulus fibrosus.